Almost all lawn and turf maintenance equipment utilize hydraulic powering systems to drive, steer and stop the equipment. Hydraulic systems are also used to power the specific purpose implements attached to such equipment to perform specific lawn and turf maintenance tasks. For example, in the case of a fairway mower, a hydraulic system is used to provide steering, forward and reverse movement, to provide braking for all wheels in a straight line and to control brake bias when attempting to decrease the turning radius. Hydraulic systems also raise, lower, activate, engage, back draft, back spin and back wash specific purpose implements. Depending on the number of functions to be performed, a single piece of equipment may contain up to 30 hydraulic hoses.
At the core of the hydraulic system is a hydraulic pump which may be internal or external to the main hydraulic reservoir. In this reservoir, hydraulic fluid is stored or pressurized. Fluid temperatures may range from 250.degree. F. to 550.degree. F. depending on the amount of power to be delivered by each hose in order to activate a given function. As seen in FIG. 1, conventional single wall hydraulic hoses 1 typically are fabricated using rubber like material which may be reinforced with a steel, aluminum or other metal or synthetic mesh woven interior fabric. Ferrel portions 6 are capped at each end with a threaded tightening bolt 3 secured with free bolt 4. A pressure fit is created with hard line 5 at one end from the hydraulic reservoir or pump and at hard line 5 at the other end going to a specific purpose attachment. The inside of the hose is represented as 2. The ferrel portion 6 is fitted around hose 1 by crimp 7.
Such conventional single wall hoses are known to frequently rupture and leak under pressure regardless of the age of the hose. Repeated bending and crimping, freeze and thaw cycles, stress caused by heat and pressure, human error in production, improper replacement and untimely maintenance are all factors which lead to frequent ruptures and leaks in conventional single wall hoses. A microscopic pinhole in a conventional single wall hose will explode under pressure spewing hot pressurized liquid onto the equipment, the operator and into the environment.
The use of fabric deflection and disbursement shields has helped to prevent injury to the operators; however, the environment still remains unprotected. Even the use of an alarm signaling a break in a hose may not prevent the blistering fluid from escaping into the environment and burning the turf. Such an accident will cause an unsightly brown area to appear in the turf creating a turf care crisis which can only be remedied over time and at extraordinary expense. Regardless of whether the turf is a professional sporting stadium, a resort golf course or a public park, the results of a break in a hydraulic hose on turf care equipment may be disastrous.
For the foregoing reasons there is a need for a dual containment hydraulic system which at a relatively low cost protects the operator from the harm and the environment from the damage caused by a hydraulic hose rupture and allows for continued operation or automatic shutdown of the maintenance equipment.